Like the ::DotLock locker, but then in an NFS-safe fashion. Over NFS, the creation of a file is not atomic. The ::DotLock locker depends on an atomic open system call, hence in not usable to lock a folder which accessed over NFS. The ::NFS locker is therefore more complicated (so therefore slower), but will work for NFS --and for local disks as well.

Fatal error: the specific package (or one of its superclasses) does not implement this method where it should. This message means that some other related classes do implement this method however the class at hand does not. Probably you should investigate this and probably inform the author of the package.

A lock file was found which was older than the expiration period as specified with the new(timeout) option. It is impossible to remove that lock file, so we need to wait until it vanishes by some external cause.